I. Field of the Invention
The present invention relates to electrical connectors and, more particularly, is directed towards a modular connector or jack which is designed to couple a modular plug to a printed circuit board.
II. Description of the Related Art
Modular jacks for coupling modular plugs to printed circuit boards are well known in the art. See, for example, my prior U.S. Pat. Nos. 4,457,570; 4,501,464; and 4,717,217. The modular jacks described in my earlier patents are all characterized by the provision of a dielectric housing and a plurality of side-by-side conductors located within the housing. Each of the conductors includes a spring contact portion at the front of the housing for mating with a contact terminal of a mating modular plug, an end portion at the rear of the housing for connection to a printed circuit board, and an intermediate portion disposed between the spring contact portion and the end portion. The conductors are further characterized in that the spacing between adjacent spring contact portions is less than the spacing between adjacent end portions. For example, the spacing between adjacent spring contact portions is preferably 0.040" in order to properly mate with the contact terminals of a modular plug. Further, the spacing at the end portions is generally 0.050" in order to mate with standard grid spacing for a printed circuit board (PCB). The fact that the spring contact portions at the front end of the connector are spaced differently from the end portions at the rear end of the connector shall be referred to hereinafter as differential spacing.
In addition, the spacing at the rear of the housing where the end portions are located are formed in two rows which are themselves spaced apart a distance equal to twice the adjacent conductor spacing. This pattern of the end portions forms what will be referred to hereinafter as an alternating, staggered array.
Another characteristic of my above-noted prior U.S. patents is that the spring contact portions of the conductors enter the plug-receiving cavity from the rear towards the front thereof. A number of other modular jacks have been designed whereby the spring contact portions enter the plug-receiving-cavity from the front and are angled towards the rear of the cavity. See, for example, U.S. Pat. Nos. 4,210,376; 4,269,467 and 4,296,991. The conductors in these latter jacks also exhibit differential spacing, and the end portions, which are coupled to the PCB, are also arranged in an alternating, staggered array.
Recently, modular jacks have developed noise problems. These generally stem from unwanted harmonics or noise from an adjacent line. Such noise could also come from radiation in the air or on the cable, or the noise could be internally coupled from the outputs of different devices. The tiny chips with which the modular jacks are utilized to run at very high frequencies, which also generates noise in the cabinet.
The danger of noise, of course, is that it could produce a variation in the amplitude of the signals on the lines. This could, in turn, result in a false positive, or could undesirably cancel another signal.
It has therefore recently become apparent that some type of filtering mechanism is necessary for use with these modular jacks for eliminating or greatly reducing this unwanted noise. It is towards this end that the present invention is advanced.